Hello, I'd like to help you with your question.
Yes, what you have heard your wife doing sounds very serious. She seems either very overwhelmed to the point that she is breaking down, or she has a more serious mental health disorder. At the very least, she is hurting her children who need to be removed from her care. The children will suffer mental health issues if left with her and the abuse continues.
If you cannot get her to see a mental health professional, then you may have to resort to contacting the police with the information you have recorded. Tell them that you were concerned about her and that you found she is hurting the kids and acting strangely when you are not at home. Be prepared to prove that you were out of town when your wife claims you hurt her, just in case the police ask.
Another option is to talk to your local ER to see if you can file to have your wife admitted to the hospital. Let the doctor know about your recording and that you are concerned about your wife's safety at home on her own. They will let you know if there is enough information to admit your wife to the hospital against her will. At least she will receive an evaluation and care to help her become more stable.
Depending on the children's ages, you may also want to get them mental health care. Being abused as they are, it is going to affect them. They may develop depression, anxiety
or other emotional disorders. Talk to their doctors about your options.
I hope this has helped you,